
/**
 * @Project : Clion_ProgrammingExercises
 * @File : 0319
 * @Author : WangRuoyu 
 * @Date : 2023/5/27 10:57
 */

#include "iostream"
#include "math.h"

using namespace std;

class Solution {
public:
    int bulbSwitch(int n) {
        return (int) sqrt(n + 0.5);
    }
};

int main() {
    Solution sl;
    printf("%d\n", sl.bulbSwitch(100));
    return 0;
}